Process of flame treating coated materials



PROCESS OF FLAME 'IAREATIN-G .COATED MATERIALS Filed Oct. 4, 1934Patented Nov. 2, 1937 UNITED ASTATES PATENT oFFlci-i I PROCESS OF FLAMETREATING COATD MATERIALS AJulian L. Schueler, Kokomo, Ind., assigner, bymesne assignments, to C. W. La Porte, Peoria, f lll., and J: L.Schueler, Kokomo, Ind., trustees Application ctober 4, 1934, SerialNo.'746,859

Claims.

This invention relates to a process for the treatment of coated iron andsteel materials. It is applicable particularly to coated wires, round',at, shaped, strips, etc., whether or not they be in- 1 5 tended forfabrication. In the ensuing descrip- 15 rial, to render the coating moresmooth and even,

and otherwise to impart a beneficial effect to the coating. These andother objects are attained by the application of ames tothe coatedmaterial for a period of time and under conditions of temperature, allashereinafter set-iout. An apparatus suitable for this purpose isillustrated in the accompanying drawing wherein is shown a number ofwires emerging from a coating bath to travel in parallelism through aiiame wave which 25 is shown as undulating between upper and lowerdeecting surfaces illustrated in vertical section to better exhibit theconstruction. l In carrying out this invention, particularly in the caseof wires, I utilize a pan P in which is 3QV contained a bath B of moltenzinc at a suitable galvanizing temperature, perhaps about 860 degrees F.Through this bath may be drawn a number of wires w in parallelism.Immediately upon leaving the bath, each wire i s taken through 35 acoating regulator R which removes `dross, skimmings, and grosserarticles, and also reduces the amount of coating remaining on the wireto'a point at which a benecial treatment by arnes may be practiced. Theweight of coating material 40 so removed from each wire may perhaps be50% or more, the amount being subject to the setting of the regulator.

Upon leaving the coating regulators the wires travel side by sidethrough a ame apparatus 45 which may comprise upper and lower deflectorsurfaces U and L, respectively. By preference, these surfaces are slopedupwardly very slightly,

as shown in the drawing. These deflector surfaces which desirably areconstituted by refrac- 50 tory blocksdeine a. space which is open on allto being guided by rollers G on their way to take-*r 55 up reels. Theupper and lower deflector surfaces confined practic are adjustablerelative to each other, so that the space between them may be varied asdesired.l

Projected from a line of burner openings O into the space from the endthereof which is proximateto the bath is a waving llame sheet F which, 5as shown, proceeds downwardly and forwardly from the upper deflectorsurface to strike thel lower deector surface, and then reboundtherefrom, and again rebound from the upper deflector surface, and so onthrdughout the length of the t ame apparatus. The flame sheet whichthusv undulates throughout the space between the two deflector surfacesis impinged against the several wires on all 4sides thereof during theirtravel through the name apparatusi Further description of the apparatusper se need not be given here inasmuch as a full explanation thereofappears in my Reissue Patent No. 19,209 dated June 12, i934.

It is my experience in the flame treating of zinc coated wire that verysatisfactory results may be 20,

obtained with certain changing temperature conditions for a' briefinterval of time. It is accordingly 'with this aspect of my inventionthat the following descri tion is particularly concerned.

I nd it ad ntageous to utilize a flame apparatus in whic may bemaintained a continuous elongated iia e sheet of between eight andeleven feet in length. The flame sheet so projected is if not entirely,within the space defined between the upper and lower de- `flectorsurfaces which accordingly may be of substantially the same length. Inpractice, these surfaces radiate considerable heat which augments thatof the flame sheet which latter, however, is alone responsible 'for thesmoothing andl 35 evening of the metallic coating so treated.

It is desirable that a temperature of from 2000 degrees F. to 2400degrees F. should obtain at the point where the waving flame sheet firststrikes the deflector surfaces. At the exit end of the 40 apparatus,this temperature is, by preference, much lower, perhaps around 1700degrees E. Accordinglyjtheremay be a differentialrange of three. tosevenhundred degrees F. between the two ends ofthe flame sheet, thepoint of highest temperature being adjacent the burners from which theflames areprojected.

Between the length of the flame, the temperature of the name, the speedof wire travel through the llame, and also the gauge of the wire itself,there is a close relationship which determines the character of theresult produced by the present flame treatment. As tothe speed of wiretravel and its consequent duration of treatment by the flame, thefollowing is noted z. g`

According to my process, it is feasible to galvanize concurrently anumber of wires varying widely1 in size, and also to treat successfullyall such wires by a flameapparatus such as hereinbefore described. Thespeed of travel for 9 gauge wire (.1485 inch diameter) may in commercialpractice be about sixty-seven feet per minute, although I have obtainedsuccessful results with a higher speed of from ninety to o ne hundredfeet per'minute. For a 15% gauge wire a commercial speed would be aboutone hundred fifty seven feet per minute. At the lower of these movementrates, the 9 gauge wire would travel through a ame zone of ten andone-half feet for approximately nine seconds, and the 151/2 gauge wirefor approximately four seconds. At higher speeds the wire will besubjected to -flame treatment for acorrespondingly shorter time. It isaccordingly optional, within a. fairly wide range, as to the speed ofwire travel and the period of flame treatment that may be selected.

I have ascertained that a very benecial effect results from the actionof flames on a molten coating of material, such aszinc, applied't'o abase, such as iron or steel. It is not the temperature per se which isresponsible for the better distribution of the coating over the base towhich smoothing of the coating which is conducive t o enhancedductilityand adherence. ,Rather itis the flame action itself, dueperhaps to its impingement upon the coating. The eiect of the a-me issatisfactory when it is applied at temperatures within the range abovesuggested, and also when the temperature conditions are such that thereis a progressive decrease in the temperature during the period of ametreatment.

From the foregoing description it is manifest that exibilitycharacterizes the operating conditions surrounding a successfullame-treatment such as this invention is concernedwith. Al-A superiorsmoothness'and evenness which comprises moving such materials at a speeddependent upon the thickness of such materials through a zone of llametreatment of predetermined length wherein the temperature of the name.treatment is progressively decreasedin the direc- 24.00 F. and 1700 F.,the wire being required.

to encounter the point of maximum temperature rst.

3. A step in the process of galvanizing wire which consists .in movingthe wire upon which a zinc coating is still molten through a zone ofames ranging between eight and eleven feet at a speed ranging betweenftyand two hundred feet per minute, the ame temperatures ranging between2400 F.` and 1700 F.-from one end of said zone to the other.

4. The processiofY treating metal coated materials having an iron baseto produce a coating of superior smoothness and evenness, whichcomprises mcving the base upon'which the coating is in molten statethrough a zone of ame treatment of predetermined length and at a speeddependent upon the character of the coating material,- and progressivelyreducing byv a difierential range of 300 to 700 degrees F. thetemperature of the flame treatment in the direction of movement of thecoated base, the lower limit of said range being above the melting pointof said coating material.

5. The process of treating metal coated materials having an iron base toproduce a coating of superior smoothness and evenness, which coinprisesregulating the weight of coating upon the base,`moving such regulatedcoated base throughout a flame treating zone of predetermined length andat a speed dependent uponvthe weight of coating material on said base,and progressively reducing by a diierentialrange of 300 to 700 degreesF. the temperature of flame treatment in the direction of movement ofthe coated base,

the lower limit of said range being above the melting point .of saidcoating material.

JUmAN L. SoHo-Erna.

